William J. Weadock

Stress Urinary Incontinence: Relative Importance of Urethral Support and Urethral Closure Pressure

PURPOSE Treatment strategies for stress incontinence are based on the concept that urethral mobility is the predominant causal factor with sphincter function a secondary contributor. To our knowledge the relative importance of these 2 factors has not been assessed in properly controlled studies. MATERIALS AND METHODS The Research on Stress Incontinence Etiology project is a case-control study that compared 103 women with stress incontinence and 108 asymptomatic controls in groups matched for age, race, parity and hysterectomy. Urethral closure pressure, urethral and pelvic organ support, levator ani muscle function and intravesical pressure were measured and analyzed using logistic regression and multivariable modeling. RESULTS Mean +/- SD maximal urethral closure pressure was 42% lower in cases (40.8 +/- 17.1 vs 70.2 +/- 22.4 cm H(2)O, d = 1.47). Lesser effect sizes were seen for support parameters, including resting urethral axis and urethrovaginal support (d = 0.41 and 0.50, respectively). Other pelvic floor parameters, including genital hiatus size and urethral axis during muscle contraction (d = 0.60 and 0.58, respectively), differed but levator strength and levator defect status did not. Maximum cough pressure, which is an assessment of stress on the continence mechanism, was also different (d = 0.43). After adjusting for body mass index the maximal urethral closure pressure alone correctly classified 50% of cases. Adding the best predictors for urethrovaginal support and cough strength to the model added 11% of predictive ability. CONCLUSIONS The finding that maximal urethral closure pressure and not urethral support is the factor most strongly associated with stress incontinence implies that improving urethral function may have therapeutic promise.

MRI of Sonographically Indeterminate Adnexal Masses

OBJECTIVE The purpose of this study was to assess the ability of MRI to characterize sonographically indeterminate adnexal masses and to define the sonographic features contributing to indeterminate diagnoses. MATERIALS AND METHODS Two blinded radiologists retrospectively reviewed the MRI examinations of 87 patients with 95 sonographically indeterminate adnexal masses. Reviewers determined the origin of a mass, its tissue content (cystic, solid, complex cystic, or cystic and solid), tissue characteristics (fat, blood, fibrous, or leiomyomatous), and benignity versus malignancy. Sonograms were reviewed by three reviewers to determine the origin of a mass, its tissue content, and reasons for an indeterminate diagnosis. Sensitivity and specificity of MRI were calculated, and agreement of sonography and MRI with the final diagnosis was determined using kappa statistics. The final diagnosis was determined by histopathology, surgical findings, or imaging or clinical follow-up. RESULTS The sensitivity of MRI for identifying malignancy (n = 5) was 100% and its specificity for benignity (n = 90) was 94%. Excellent agreement was seen between MRI and the final diagnosis for determining the origin (kappa = 0.93), tissue content (kappa = 0.98), and tissue characteristics (kappa = 0.91) of a mass. Sonography had poor agreement with the final diagnosis for the origin (kappa = 0.19) and tissue content (kappa = 0.33) of a mass. The main reasons for indeterminate sonographic diagnoses were the inability to determine origin because of location and large mass size and the appearances of purely solid or complex cystic masses. CONCLUSION Sonographically indeterminate adnexal masses of uncertain origin and solid or complex cystic content benefit from further evaluation with MRI, which is highly accurate for identifying the origin of a mass and characterizing its tissue content, obviating surgery.

Value of delayed hypointensity and delayed enhancing rim in magnetic resonance imaging diagnosis of small hepatocellular carcinoma in the cirrhotic liver

To determine the diagnostic utility of delayed hypointensity and delayed enhancing rim on magnetic resonance imaging (MRI) as indicators of hepatocellular carcinoma (HCC) in arterially enhancing nodules ≤5 cm in the cirrhotic liver and determine the features that best predict HCC.

Possible biliary disease: Diagnostic performance of high-spatial-resolution isotropic 3D T2-weighted MRCP

PURPOSE To retrospectively assess the diagnostic performance of magnetic resonance cholangiopancreatography (MRCP) performed by using a high-spatial-resolution isotropic three-dimensional (3D) fast-recovery fast spin-echo (FSE) sequence with parallel imaging for the evaluation of possible biliary disease. MATERIALS AND METHODS This HIPAA-compliant study was approved by the institutional review board; informed consent was waived. Ninety-five patients (58 female, 37 male; mean age, 51 years; range, 15-91 years) underwent MRCP by using the respiratory-triggered isotropic 3D fast-recovery FSE sequence and endoscopic or percutaneous direct visualization between March 2003 and June 2007. Two independent readers evaluated the MRCP images for strictures, dilatation, and intraductal filling defects. Sensitivity, specificity, and interobserver agreement (kappa statistics) were determined. RESULTS The respective sensitivity and specificity for strictures, dilatation, and intraductal filling defects (all choledocholithiasis) were 86% (40 of 47) and 94% (45 of 48), 98% (57 of 58) and 100% (37 of 37), and 68% (19 of 28) and 97% (65 of 67) for reader 1 and 88% (41 of 47) and 94% (45 of 48), 96% (56 of 58) and 100% (37 of 37), and 75% (21 of 28) and 99% (66 of 67) for reader 2. The sensitivity for stones larger than 3 mm was 94% (15 of 16) for reader 1 and 100% (16 of 16) for reader 2, whereas the sensitivity for stones 3 mm or smaller was 33% (four of 12) for reader 1 and 42% (five of 12) for reader 2. Agreement between readers was good to excellent, with kappa values of 0.76, 0.85, and 0.98 for strictures, dilatation, and choledocholithiasis, respectively. CONCLUSION MRCP by using the respiratory-triggered isotropic 3D fast-recovery FSE sequence with parallel imaging demonstrates excellent diagnostic capabilities for possible biliary disease, although it is limited for stones 3 mm or smaller in size.

Sonographic Twinkling Artifact for Renal Calculus Detection: Correlation with CT

PURPOSE To retrospectively correlate sonographic color Doppler twinkling artifact within the kidneys with unenhanced computed tomography (CT) in the detection of nephrolithiasis. MATERIALS AND METHODS Institutional review board approval was obtained for this retrospective HIPAA-complaint investigation, and the informed consent requirement was waived. Sonographic imaging reports describing the presence of renal twinkling artifact between January 2008 and September 2009 were identified. Subjects who did not undergo unenhanced abdominal CT within 2 weeks after sonography were excluded. Ultrasound examinations were reviewed by three radiologists working together, and presence, number, location, and size of renal twinkling artifacts were documented by consensus opinion. Sonographic findings were correlated with unenhanced CT (5-mm section width, no overlap) for nephrolithiasis and other causes of twinkling artifact. The number, location, and size of renal calculi at CT were documented. RESULTS The presence of sonographic renal twinkling artifact, in general, had a 78% (95% confidence interval: 0.66, 0.90) positive predictive value for nephrolithiasis anywhere in the kidneys at CT. The true-positive rate of twinkling artifact for confirmed calculi at CT was 49% (73 of 148 twinkling foci), while the false-positive rate was 51% (75 of 148 twinkling foci). The overall sensitivity of twinkling artifact for the detection of specific individual renal calculi observed at CT was 55% (95% confidence interval: 0.47, 0.64). CONCLUSION While renal twinkling artifact is commonly associated with nephrolithiasis, this finding is relatively insensitive in routine clinical practice and has a high false-positive rate when 5-mm unenhanced CT images are used as the reference standard. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11102128/-/DC1.

3D excretory MR urography: Improved image quality with intravenous saline and diuretic administration

To assess the effect of diuretic administration on the image quality of excretory magnetic resonance urography (MRU) obtained following intravenous hydration, and to determine whether intravenous hydration alone is sufficient to produce diagnostic quality studies of nondilated upper tracts.

Magnetic Resonance Imaging and 3-Dimensional Analysis of External Anal Sphincter Anatomy

OBJECTIVE: To use magnetic resonance images of living women and 3-dimesional modeling software to identify the component parts and characteristic features of the external anal sphincter (EAS) that have visible separation or varying origins and insertions. METHODS: Detailed structural analysis of anal sphincter anatomy was performed on 3 pelvic magnetic resonance imaging (MRI) data sets selected for image clarity from ongoing studies involving nulliparous women. The relationships of anal sphincter structures seen in axial, sagittal, and coronal planes were examined using the 3-D Slicer 2.1b1 software program. The following were requirements for sphincter elements to be considered separate: 1) a clear and consistently visible separation or 2) a different origin or insertion. The characteristic features identified in this way were then evaluated in images from an additional 50 nulliparas for the frequency of feature visibility. RESULTS: There were 3 components of the EAS that met criteria as being “separate” structures. The main body (EAS-M) is separated from the subcutaneous external anal sphincter (SQ-EAS) by a clear division that could be observed in all (100%) of the MRI scans reviewed. The wing-shaped end (EAS-W) has fibers that do not cross the midline ventrally, but have lateral origins near the ischiopubic ramus. This EAS-W component was visible in 76% of the nulliparas reviewed. CONCLUSION: Three distinct external anal sphincter components can be identified by MRI in the majority of nulliparous women.

Abdominal applications of diffusion-weighted magnetic resonance imaging: Where do we stand

Diffusion-weighted imaging (DWI) is one of the magnetic resonance imaging (MRI) sequences providing qualitative as well as quantitative information at a cellular level. It has been widely used for various applications in the central nervous system. Over the past decade, various extracranial applications of DWI have been increasingly explored, as it may detect changes even before signal alterations or morphological abnormalities become apparent on other pulse sequences. Initial results from abdominal MRI applications are promising, particularly in oncological settings and for the detection of abscesses. The purpose of this article is to describe the clinically relevant basic concepts of DWI, techniques to perform abdominal DWI, its analysis and applications in abdominal visceral MR imaging, in addition to a brief overview of whole body DWI MRI.

Sonography of Uterine Abnormalities in Postpartum and Postabortion Patients A Potential Pitfall of Interpretation

The interpretation of postpartum and postabortion uterine abnormalities on sonography can be challenging. The purpose of this study was to identify misleading imaging features that lead to inclusion of a uterine arteriovenous malformation (AVM) in the differential diagnosis of a uterine abnormality because consideration of this diagnosis can potentially alter patient treatment.

Technical Principles of MR Angiography Methods

Magnetic resonance provides a wide variety of possibilities for arterial and venous blood vessel imaging in all vascular territories. This article provides a brief review of the technical principles of MR angiography. The first section is dedicated to non-contrast-enhanced angiography techniques and includes several distinct approaches: time-of-flight, phase contrast, triggered angiography non-contrast-enhanced, and balanced steady-state free precession. The second section relates to the contrast-enhanced and time-resolved contrast-enhanced MR angiography methods. The latest technical developments in MR imaging hardware, sequences and software, coil technology, and reconstruction capability allow dynamic MR angiography performance similar to CT angiography, without risks of iodine contrast agent and ionizing radiation exposure.